Re: Cooling technique for Jupiter brains

From: Jeff Davis (
Date: Wed Feb 09 2000 - 13:15:03 MST


On Mon, 07 Feb 2000 21:01:31 -0800,
Spike Jones <> wrote:

>I worked on the orbit mechanics and found that if the material were in
>the same orbital plane as the planet, then all you need to do is figure
>out how to stop the rotation of the planet, or rather, tide lock it with
>the sun. The material could be rotating in the opposite direction as

Funny, but I pictured the Jupiter brain as being alone in space. Not
revolving around a star and not rotating. So I didn't worry about the
cooling tubes moving relative to the eliptical orbits of the coolant rings.
 If this "tide lock" thing works to keep everything aligned, then terrific,
but I would worry--in the case where the JB is a "satellite" in orbit
around a star or other object, and possibly in a "system" with other
orbiting stuff--that the elliptical orbits of the coolant would be utterly
unmanageable due to the gravitational disturbance caused by the star and
the other stuff.

What I did worry about, in the situation as I pictured it originally, the
self-sufficient JB happily transiting deep space, was the possibility of
the precession of the coolant orbits, due to the discontinuity/drop in
gravitational force which the coolant/ring material would experience when
it plunged below the surface (ie through the coolant passage) of the JB.
At a radial distance less than the full radius of a spherically symmetric
object, the gravitational force of the material which lies outside that
radial distance--the gravitational attraction of the outer layers of the
object, pulling from all around--balances out to zero, leaving only the
gravitational attraction of the material which is interior to that radius,
ie, concentrated all to one side rather than all around. Certainly this
would alter the shape of the orbit from a "constant" ellipse to a
continuously varying ellipse in the region of the coolant passage as it
plunged ever deeper within the JB. The shape of the coolant tube would
be/could be designed to accomodate this, but what seems to me more
challenging is the "precession" problem. What happens to the "standard"
elliptical orbit of the material exiting the tube relative to the orbit it
had when it went in? Rotating the JB and its coolant tube to accomodate a
precession (if there is one) might/should work, if there's only one tube,
but if you have two coolant flows skewed 90 degress from one
another,...things start to become markedly less elegant than they seemed
originally (crumples up sketch, tosses it in dumper, sees nobel prize
dematerialize from mantlepiece).

The non-standard nature of this problem would probably make it quite
interesting to someone jaded by long experience with "ordinary" orbital
mechanics calculations. One thing's for sure, it's more than I can
handle. Spike? (Amara, you should try this only if you find it pleasant
and self-fulfilling. ;-) )

                        Best, Jeff Davis

           "Everything's hard till you know how to do it."
                                        Ray Charles

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